/*
 * Copyright (c) 2007-2012, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package com.sun.org.apache.bcel.internal.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
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 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
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 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
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 *    if and wherever such third-party acknowledgments normally appear.
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 * SUCH DAMAGE.
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 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import com.sun.org.apache.bcel.internal.Constants;
import java.io.*;

/**
 * This class represents a local variable within a method. It contains its
 * scope, name, signature and index on the method's frame.
 *
 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @see     LocalVariableTable
 */
public final class LocalVariable implements Constants, Cloneable, Node, Serializable {
    private int start_pc; // Range in which the variable is valid
    private int length;
    private int name_index; // Index in constant pool of variable name
    private int signature_index; // Index of variable signature
    private int index; /* Variable is `index'th local variable on
                       * this method's frame.
                       */

    private ConstantPool constant_pool;

    /**
     * Initialize from another object. Note that both objects use the same
     * references (shallow copy). Use copy() for a physical copy.
     */
    public LocalVariable(LocalVariable c) {
        this(c.getStartPC(), c.getLength(), c.getNameIndex(), c.getSignatureIndex(), c.getIndex(), c.getConstantPool());
    }

    /**
     * Construct object from file stream.
     * @param file Input stream
     * @throws IOException
     */
    LocalVariable(DataInputStream file, ConstantPool constant_pool) throws IOException {
        this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), constant_pool);
    }

    /**
     * @param start_pc Range in which the variable
     * @param length ... is valid
     * @param name_index Index in constant pool of variable name
     * @param signature_index Index of variable's signature
     * @param index Variable is `index'th local variable on the method's frame
     * @param constant_pool Array of constants
     */
    public LocalVariable(int start_pc, int length, int name_index, int signature_index, int index, ConstantPool constant_pool) {
        this.start_pc = start_pc;
        this.length = length;
        this.name_index = name_index;
        this.signature_index = signature_index;
        this.index = index;
        this.constant_pool = constant_pool;
    }

    /**
     * Called by objects that are traversing the nodes of the tree implicitely
     * defined by the contents of a Java class. I.e., the hierarchy of methods,
     * fields, attributes, etc. spawns a tree of objects.
     *
     * @param v Visitor object
     */
    public void accept(Visitor v) {
        v.visitLocalVariable(this);
    }

    /**
     * Dump local variable to file stream in binary format.
     *
     * @param file Output file stream
     * @throws IOException
     */
    public final void dump(DataOutputStream file) throws IOException {
        file.writeShort(start_pc);
        file.writeShort(length);
        file.writeShort(name_index);
        file.writeShort(signature_index);
        file.writeShort(index);
    }

    /**
     * @return Constant pool used by this object.
     */
    public final ConstantPool getConstantPool() {
        return constant_pool;
    }

    /**
     * @return Variable is valid within getStartPC() .. getStartPC()+getLength()
     */
    public final int getLength() {
        return length;
    }

    /**
     * @return Variable name.
     */
    public final String getName() {
        ConstantUtf8 c;

        c = (ConstantUtf8) constant_pool.getConstant(name_index, CONSTANT_Utf8);
        return c.getBytes();
    }

    /**
     * @return Index in constant pool of variable name.
     */
    public final int getNameIndex() {
        return name_index;
    }

    /**
     * @return Signature.
     */
    public final String getSignature() {
        ConstantUtf8 c;
        c = (ConstantUtf8) constant_pool.getConstant(signature_index, CONSTANT_Utf8);
        return c.getBytes();
    }

    /**
     * @return Index in constant pool of variable signature.
     */
    public final int getSignatureIndex() {
        return signature_index;
    }

    /**
     * @return index of register where variable is stored
     */
    public final int getIndex() {
        return index;
    }

    /**
     * @return Start of range where he variable is valid
     */
    public final int getStartPC() {
        return start_pc;
    }

    /**
     * @param constant_pool Constant pool to be used for this object.
     */
    public final void setConstantPool(ConstantPool constant_pool) {
        this.constant_pool = constant_pool;
    }

    /**
     * @param length.
     */
    public final void setLength(int length) {
        this.length = length;
    }

    /**
     * @param name_index.
     */
    public final void setNameIndex(int name_index) {
        this.name_index = name_index;
    }

    /**
     * @param signature_index.
     */
    public final void setSignatureIndex(int signature_index) {
        this.signature_index = signature_index;
    }

    /**
     * @param index.
     */
    public final void setIndex(int index) {
        this.index = index;
    }

    /**
     * @param start_pc Specify range where the local variable is valid.
     */
    public final void setStartPC(int start_pc) {
        this.start_pc = start_pc;
    }

    /**
     * @return string representation.
     */
    public final String toString() {
        String name = getName(),
                        signature = Utility.signatureToString(getSignature());

        return "LocalVariable(start_pc = " + start_pc + ", length = " + length + ", index = " + index + ":" + signature + " " + name + ")";
    }

    /**
     * @return deep copy of this object
     */
    public LocalVariable copy() {
        try {
            return (LocalVariable) clone();
        } catch (CloneNotSupportedException e) {
        }

        return null;
    }
}
